Magnetic separator

ABSTRACT

A rotating drum, slightly inclined from the horizontal, is provided adjacent opposite ends with discharge openings, and the interior of the drum is provided with spiral ribs which tend to feed material toward the higher end of the drum to be discharged through the opening adjacent such end of the drum. Magnetic means is arranged externally of the drum and longitudinally thereof to cause pieces of magnetic material in the mixture to adhere to the side of the drum to be carried upwardly and then released to drop to the bottom of the drum, such material dropping vertically rather than perpendicularly to the axis of the drum so that it gradually works its way toward the lower end of the drum to be discharged through the lower discharge opening.

United States Patent [72] Inventor Byron C. Schmid 2101 16th St. N. Washington, D.C. 20009 [21] Appl. No 801,482 [22] Filed Feb. 24,1969 145] Patented July 27. 1971 [54} MAGNETIC SEPARATOR 10 Claims, 6 Drawing-Figs.

[52] 0.5. CI 209/225, 209/39, 209/46. 209/152 [51] Int. Cl B03c 1/14 [50] Field oi Search 209/225, 223 R. 214,231, 221, 228. 39

[56] References Cited UNITED STATES PATENTS 466,513 1/1892 Reed 209/225 3,087,616 4/1963 Pierson r 209/221 3,458,040 7/1969 Schmid 209/127 X 3,458,041 7/]969 Schmid 209/127 X FOREIGN PATENTS 725,l l0 5/1932 France 209/224 681.907 10/1930 Germany 209/39 Primary Examiner-Frank W. Lutter Assistant E.raminer-- Ralph J. Hill Attorney-Alexander B. Blair ABSTRACT: A rotating drum, slightly inclined from the horizontal, is-provided adjacent opposite ends with discharge openings, and the interior of the drum is provided with spiral ribs which tend to feed material toward the higher end of the drum to be discharged through the opening adjacent such end of the drum. Magnetic means is arranged externally of the drum and longitudinally thereof to cause pieces of magnetic material in the mixture to adhere to the side of the drum to be carried upwardly and then released to drop to the bottom of the drum, such material dropping vertically rather than perpendicularly to the axis of the drum so that it gradually works its way toward the lower end of the drum to be discharged through the lower discharge opening.

PATENTEUJULZTIBH 3,595,391

SHEET 1 OF 3 NVENTOR b y/0N C. S h

ATTORNEY MAGNETIC SEPARATOR FIELD OF THE INVENTION jacent the drum serving to cause magnetic material to be fed in the opposite direction to effect a complete separation of the materials.

SUMMARY OF THE INVENTION An elongated drum is supported above a base arranged at an angle to the horizontal and'having means for adjusting its angularity, depending upon the materials being separated. The drum is supported on rollers adjacent opposite ends to rotate on its axis and a motor has gear connection with the drum to effect constant rotation thereof in one direction. Adjacent opposite ends thereof, the drum is provided with discharge openings through which material falls into collecting casings. Spiral ribs are fixed against the inner face of the drum and non magnetic material, tending to be retained by gravity in the bottom of the drum, is fed by the spirals toward the upper end of the drum, the spiral rigs thus acting as a constantly operating conveyor.

A magnet, either of the permanent or electromagnetic type, is arranged adjacent the drum externally thereof. This magnet is elongated and extends throughout the greater part of the distance between the collecting casings and has pole pieces adjacent the drum so that any magnetic particles within the drum, instead of remaining in the bottom thereof by gravity, will be caused to magnetically adhere to the drum to move upwardly therewith at one side thereof. Before the magnetic particles reach the top of the drum, the magnetic forces affecting them will taper off and will cease by the time the magnetic particles reach the top of the drum. These particles, therefore, willdrop from the top of the drum to the bottom thereof. Since the drum is inclined from the horizontal, the magnetic particles which drop to the bottom of the drum contact the latter at a relatively lower point therealong. This repeated lifting and dropping of the magnetic materials causes them to progress toward the lower end of the inclined drum to fall through the discharge openings at such end of the drum to be collected in the associated collecting casing.

The invention is capable of a number of embodiments. For example, the elongated magnet may be of substantially E- shaped cross section to form three legs or pole pieces the center one of which may have a coil winding forming an electromagnet. The other legs or pole pieces extend into relative proximity to the drum and the flow of magnetic flux from the pole pieces referred to will flow into the drum and back to the center pole piece to proiide the magnetic attraction for magnetic materials being separated. In one form of drum, the structure comprises inner and outer cylindrical elements and an intermediate layer made up of alternate sections of magnetic and nonmagnetic materials to tend to break up the continuous flow of magnetic flux around the drum. Those magnetic sections of the intermediate layer of the drum as they pass the magnet, however, facilitate the flow of flux to the magnetic particles within the drum.

In a modification of the structure of the drum, inner and outer nonmagnetic cylindrical shells have arranged therebetween an intermediate layer of magnetic material. The intermediate layer, however, is quite thin and therefore does not tend to carry the flow of magnetic flux too far around the drum. In another modification, longitudinal abutments secured to the inside of the drum extend between the turns of the spiral ribs to tend to jolt loose from the drum nonmagnetic particles which may tend to adhere to the drum. In a still further modification, the magnet is altered to tend to attenuate the flow of magnetic flux if the material being separated so requires. In this case an extra pole piece may be employed having a nonmagnetic element between it and the body of the magnet to limit the flow of flux therethrough. The upper pole piece may be similarly formed with nonmagnetic inserts to reduce the magnetic pull toward the top of the drum, and such pole piece may be provided with an extended end portion longitudinally of the drum, and curving upwardly and away therefrom, toward the top of the drum.

For the purpose of adjusting the magnetic means relative to the cylinder in accordance with the material being separated, a support is provided for the magnet which permits the latter to be adjusted upwardly or downwardly, toward and away from the drum and tilted relative to the drum.

BRIEF DESECRIPTION OF THE DRAWINGS FIG. I is a elevation of the apparatus as a whole;

FIG. 2 is a section on line 2-2 of FIG. 1, parts being shown in elevation;

FIG. 3 is a similar cross section ofa modified type of drum;

FIG. 4 is a similar view of another modification of the drum;

FIG. 5 is a similar view showing a modified type of magnet means; and

FIG. 6 is an inner face view of the magnet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the numeral 10 designates a bottom plate as a whole to which is pivotally connected as at 12 a base plate 14 for supporting the apparatus. The end of the base 14 opposite its pivot extends between vertical stanchions 16 having a plurality of openings 18 arranged on an arc of a circle concentric with the axis ofthe pivot pin 12. Transverse pins 20 extending through each stanchion 16 are engageable with the base 14 to support it in any adjusted angular position relative to the horizontal.

A drum indicated as a whole by the numeral 22 is arranged above and parallel to the base 14. This drum is elongated as shown in FIG. I and is provided adjacent each end with a circular rib 24, each of which is engageable in the grooves of rollers 26 supported by standards 28 carried by the base 14. Adjacent its lower end, the drum 22 is provided with a gear 30 meshing with a pinion 32 on the drive shaft of a motor 34, thus providing means for constantly rotating the drum 22 in one direction.

One form of the drum lO is shown in FIG. 2. This drum comprises inner and outer shells 36 and 38 concentric with each other and formed of nonmagnetic material, for example, aluminum. These shells are spaced from each other and have arranged therebetween alternate sections of magnetic material 40 and nonmagnetic material 42 for a purpose which will become apparent. Against the inner surface of the shell 36 are secured spiral ribs 44 preferably of angular section as shown in FIG. 2. As the drum is rotated, these spiral ribs act as conveyors for nonmagnetic material within the drum. Such material remains in contact with the lower portion of the drum by gravity to be fed toward the higher end of the drum and such material will be discharged from the drum through openings 46 into a collecting container 48 preferably provided with a drawer 50 adapted to be withdrawn from the casing or container 48 when the collected nonmagnetic material is to be dumped. In a manner to be described, magnetic particles in the drum 22 are fed toward the lower end thereof to be discharged through openings 52, similar to the openings 46, into a container or casing 54. This casing may be identical with the casing 48 and is preferably provided with a collecting drawer 56.

Material is supplied to the drum 22 through an axial tube 58 terminating at its outlet end substantially centrally of the length of the drum. This tube, in turn, is supplied with material through a tube 60 supplied from a hopper 62 supported as at 64. A conveyor 65 moves material from the hopper through the tube 60 and is driven by a belt 66 passing over a pulley 68 and over a pulley 70 driven by a motor 72. On the tube 60 is journaled a fan 74 connected to a pulley 76 driven by a belt 78 operated by a motor 80.

A magnet device 82 is arranged adjacent and extends longitudinally along the drum 22 FIGS, 1 and 2). Then magnetic device in this case is shown as being of the electromagnetic type and is of generally E-shape comprising a body 84, a central pole piece 86 and top and bottom pole pieces 88 and 90. A coil 92 on the center p9le piece 86 is energized in suitable manner to create the flow of flux upwardly and to the left through pole piece 88 and downwardly to the left through pole piece 90. The magnetic flux obviously flows from the ends of the pole pieces 88 and 90 to the pole piece 86. The flux thus flowing passes through the adjacent portion of the drum 22, the flow being assisted to some extent by the adjacent magnetic bodies 40, thus causing pieces of magnetic material to adhere to the upwardly moving side of the drum, that is, the right-hand side in FIG. 2. After passing upwardly beyond the pole piece 88, the magnetic attraction of the material being carried upwardly by the drum will diminish and will disappear when the material reaches the top of the drum, whereupon this material will drop into the bottom of the drum to be picked up again by the drum and moved upwardly. Thus the magnetic material will be repeatedly lifted and dropped. Due to the inclination of the drum the magnetic material, drooping vertically by gravity, will gather in the bottom of the drum at a point closer to the lower end of the drum than the point at which it was picked up. The magnetic material thus will not be affected by the conveying action of the spirals 44 and accordingly will progress toward the lower end of the drum to be dropped through one of the openings 52 into the casing 54. At

the same time, the helical rigs 44 will convey the nonmagnetic material toward the higher end of the drum. This material will not be affected by the magnet 82 and thus will tend to slide circumferentially relative to the drum as the latter turns, remaining in the bottom of the drum to be conveyed to the higher end thereof. This material will be discharged through one of the openings 46 into the casing 48.

It is desirable to adjust the magnet 82 to secure proper separation of materials of different types and particle sizes. To this end, each end of the magnet 82 is connected to an outwardly extending arm 94 by a wingnut 96. The loosening of the wingnuts permits the magnet 82 to be tilted on the axis of the wingnut to move the free ends of the pole pieces 88 and 90 respectively toward and away from the drum and vice versa. The arm 94 is slotted as at 98 to receive a bolt 100 passing therethrough and through a slot 102 in a vertical standard 104 supported on an extension 106 of the base 14. A wingnut 108 on each bolt 100 is tightened to hold the arms 94 and 104 in fixed adjusted positions. By loosening the wingnuts 108, the magnet 82 may be swung about the common axis of the bolts 100 or may be moved toward and away from the drum 22 or raised and lowered relative thereto.

In FIG. 3 the magnet device 82 may be identical with the one previously described and the parts thereof have been indicated by the same reference numerals. In this case, a drum 110 is employed having inner and outer shells 112 and 114 of nonmagnetic material as in the previous case, except that the filler 116 therebetween is a continuous cylinder of magnetic material. This cylinder, however, is quite thin to reduce its effect in conducting magnetic flux circumferentially of the drum. The helical ribs 44 are also used in this form of the invention for the same purpose as before.

In FIG. 4 the magnetic device 82 again may be identical with that in FIG. 2, but the drum 118 in this case will be somewhat different particularly for handling certain mixtures. In this case, the drum 118 may be unitary and comprises a nonmagnetic drum body 120 having the same helical ribs 44 therein. In this case, longitudinal abutments 122 will extend longitudinally between the turns of the helical ribs 44 and may be of triangular cross section. Under some conditions, magnetizable materials flowing upwardly at the right side of the drum 118 (FIG. 4) will come within the magnetic field of the poles 88 and 90 and will be so strongly influenced thereby that they tend to remain within such field while the drum 118 continues to turn. Under such conditions, the materials referred to will slide relative to the drum and not be lifted to the top thereof to drop to the bottom thereof. To take care such materials, the abutments 122 are provided to pick up the materials and force them to turn circumferentially with the drum instead of sliding relative thereto and being fed toward the upper end of the drum (FIG. 1) by the helices 44.

In FIG. 5 a different type of magnet device 124 is associated with a drum 126 of non magnetic material provided with the same helical ribs 44. The purpose of the magnet device 124, for use with certain materials to be separated, is to spread the magnetic influence on the particles within the drum circumferentially thereof but with diminishing intensity. In this case the magnet comprises a body bar 126 having a pole iece 128 provided with a magnet coil 130, and the magnet includes a bottom pole piece 132 similar to the pole pieces previously described. In this case, a pole piece 134 is employed between the magnet and the upper end of the bar, but the flux flow through such pole piece is reduced by magnetically insulating it from the bar 126 by an insert of nonmagnetic material 136. The upper end of the bar 126 is turned inwardly and downwardly as at 138 to form a portion of a pole piece 140. This pole piece has a magnetic section 142 spaced from the end 138 by an insert of nonmagnetic material 144. From its inner end relative to the drum 126, the pole piece section 142 curves upwardly and outwardly as at 146 and is provided with a magnetic end 148 magnetically insulated from the portion 146 as at 150. The use of the nonmagnetic bodies 136, 144 and 150 diminishes the intensity of the flux flow through the associated pole pieces, while the use of the extra pole piece 134, the greater spacing of the pole piece 142 from the magnet coil 130 and upward and outward curvature of the end of the pole piece 142 attenuates the field of flow ofmagnetic flux circumferentially ofthe drum.

OPERATION Nonmagnetic particles in the drum will have no tendency to move upwardly at the rising side of the drum since they will be subject to little magnetic attraction. Thus, as the drum rotates, these particles will tend to slide downwardly to the bottom of the drum and will be picked up by the helical ribs 44 and conveyed to the higher end of the drum to be discharged into the container 48. Magnetic particles will adhere to the rising side of the drum and the magnetic attraction to which they are subjected will diminish toward and disappear at approximately the top of the drum so that these particles tend to drop vertically and not perpendicular to the axis of the drum. Thus in the absence of any force tending to move them lengthwise of the drum, the magnetic particles will drop to a lower point in the drum than at the point at which they started to rise. Thus the magnetic particles will be picked up and dropped repeatedly and will progress along the drum and be discharged into the container casing 54. This action, however, will be facilitated by the sue of the fan 74. This fan maintains a movement of air throughout the length of the drum, which is open at both ends. With the use of the fan, therefore, the magnetic particles dropping from the top of the drum will not drop directly vertically, but downwardly and to the right in FIG. 1. With the use of the fan, therefore, the magnetic particles will progress more rapidly toward the discharge openings 52. The purpose of the different types of drums and magnets have been described above.

Ordinarily, the angle of the drum from the horizontal and the rotational speed of the drum will be determined by experimentation. The rotational speed may be controlled by controlling the speed of the motor 34. Some materials will require a greater or less inclination of the drum from the horizontal for most efficient operation. This obviously can be accomplished by removing the pins 20 (FIG. 1), raising or lowering the free end of the base 14, and reinserting the pins 20.

From the foregoing it will now be seen that there is herein provided an improved magnetic separator which accomplishes all of the objects'of this invention and others, including many advantages of great practical utility and commercial importance.

As various embodiments may be made of this inventive concept, and as many modifications may be made in the embodiments hereinbefore shown and described, it is to be understood that all matter herein is to be interpreted merely as illustrative, and not in a limiting sense.

i claim:

l. A separator for materials containing a magnetic substance, comprising an elongated cylinder, means for supporting said cylinder for rotation on an axis inclined from the horizontal, means acting as a conveyor for moving toward the higher end of said cylinder nonmagnetic portions of the mixture to be separated, and a magnet elongated longitudinally of the upwardly travelling side of said cylinder and arranged in proximity thereto, said magnet having at least one pole piece tending to cause magnetic particles in the cylinder to adhere to the upwardly moving side thereof as said cylinder is rotated, the flow of magnetic flux of said magnet tapering off toward the top of said cylinder whereby magnetic particles adhering to the side of the cylinder will drop from the top thereof into engagement with the bottom of said cylinder at a point spaced from the point at which they were picked up by the cylinder due to the inclination thereof to the horizontal, whereby the repeated picking up and dropping of magnetic particles causes them to work their way to the lower end of the cylinder to be discharged therefrom.

2. A separator according to claim 1 wherein said magnet has two pole pieces extending longitudinally of said cylinder at vertically spaced points, the upper pole piece being spaced from the top of said cylinder to gradually lose its magnetic attraction to magnetic particles in said cylinder by the time such particles reach the top of said cylinder.

3. A separator according to claim 2 provided with a central longitudinally elongated pole piece, and a magnet coil surrounding such pole piece.

4. A separator according to claim 1 wherein said cylinder is provided at least at spaced points therearound with magnetizable material to assist the flow of magnetic flux through said cylinder to the pieces of magnetizable material adhering to said cylinder.

5. A separator according to claim 1 wherein said means acting as a conveyor comprises helical ribs within said cylinder, said cylinder having discharge openings therethrough adjacent the higher and lower ends of said cylinder for the discharge therethrough of nonmagnetic and magnetic materials respectively, said magnet having two pole pieces spaced vertically from each other and extending longitudinally of said cylinder.

6. A separator according to claim 5 provided with means for supporting said magnet adjacent said cylinder for tilting movement on a horizontal axis and for movement toward and away from said cylinder and vertically thereof.

7. A separator according to claim 5 wherein said cylinder is formed of inner and outer shells of nonmagnetic material and an intervening layer made up of alternate bodies of magnetic and nonmagnetic materials.

8. A separator according to claim 5 wherein said cylinder is formed of inner and outer shells of nonmagnetic material and an intervening shell formed of relatively thin magnetic material extending entirely around said cylinder.

9. A separator according to claim 5 wherein the interior of said cylinder is provided with longitudinal abutments extending between the turns of said helical ribs and of a height less than the radial width of said ribs.

10. A separator according to claim 1 wherein said magnet is provided with vertically spaced elongated pole pieces extending radially toward said cylinder, said magnet being further provided between said pole pieces with an intermediate pole piece having a coil therearound, said magnet having an upper pole piece extendin radially toward said cylinder and having its upper end curve upwar ly and away from said cylinder, at

least said last-named pole piece having inserted therein at least one body ofa non magnetic material to dampen the flow of magnetic flux toward the top of said cylinder and to attenuate the flow of said flux circumferentially around said cylinder. 

1. A separator for materials containing a magnetic substance, comprising an elongated cylinder, means for supporting said cylinder for rotation on an axis inclined from the horizontal, means acting as a conveyor for moving toward the higher end of said cylinder nonmagnetic portions of the mixture to be separated, and a magnet elongated longitudinally of the upwardly travelling side of said cylinder and arranged in proximity thereto, said magnet having at least one pole piece tending to cause magnetic particles in the cylinder to adhere to the upwardly moving side thereof as said cylinder is rotated, the flow of magnetic flux of said magnet tapering off toward the top of said cylinder whereby magnetic particles adhering to the side of the cylinder will drop from the top thereof into engagement with the bottom of said cylinder at a point spaced from the point at which they were picked up by the cylinder due to the inclination thereof to the horizontal, whereby the repeated picking up and dropping of magnetic particles causes them to work their way to the lower end of the cylinder to be discharged therefrom.
 2. A separator according to claim 1 wherein said magnet has two pole pieces extending longitudinally of said cylinder at vertically spaced points, the upper pole piece being spaced from the top of said cylinder to gradually lose its magnetic attraction to magnetic particles in said cylinder by the time such particles reach the top of said cylinder.
 3. A separator according to claim 2 provided with a central longitudinally elongated pole piece, and a magnet coil surrounding such pole piece.
 4. A separator according to claim 1 wherein said cylinder is provided at least at spaced points therearound with magnetizable mateRial to assist the flow of magnetic flux through said cylinder to the pieces of magnetizable material adhering to said cylinder.
 5. A separator according to claim 1 wherein said means acting as a conveyor comprises helical ribs within said cylinder, said cylinder having discharge openings therethrough adjacent the higher and lower ends of said cylinder for the discharge therethrough of nonmagnetic and magnetic materials respectively, said magnet having two pole pieces spaced vertically from each other and extending longitudinally of said cylinder.
 6. A separator according to claim 5 provided with means for supporting said magnet adjacent said cylinder for tilting movement on a horizontal axis and for movement toward and away from said cylinder and vertically thereof.
 7. A separator according to claim 5 wherein said cylinder is formed of inner and outer shells of nonmagnetic material and an intervening layer made up of alternate bodies of magnetic and nonmagnetic materials.
 8. A separator according to claim 5 wherein said cylinder is formed of inner and outer shells of nonmagnetic material and an intervening shell formed of relatively thin magnetic material extending entirely around said cylinder.
 9. A separator according to claim 5 wherein the interior of said cylinder is provided with longitudinal abutments extending between the turns of said helical ribs and of a height less than the radial width of said ribs.
 10. A separator according to claim 1 wherein said magnet is provided with vertically spaced elongated pole pieces extending radially toward said cylinder, said magnet being further provided between said pole pieces with an intermediate pole piece having a coil therearound, said magnet having an upper pole piece extending radially toward said cylinder and having its upper end curved upwardly and away from said cylinder, at least said last-named pole piece having inserted therein at least one body of a non magnetic material to dampen the flow of magnetic flux toward the top of said cylinder and to attenuate the flow of said flux circumferentially around said cylinder. 